Method of securing contact members



March 30, 1937.

H. -K. RICHARDSON METHOD OF SECURING CONTACT MEMBERS Filed Oct. '7, 19330 07.0 5 1 0 1 Z Z 1 g Iv 6 a 5 4 1 6 1 5 1 7 9w 1 6 1 LPII. 4 I Z m Z1-1 U1 -$PAK$|NM$ 4 Y 6 Z Patented Mar. 30, E93? Wires" sraras PATENTOFFIQE METHOD OF SECURING CONTACT MEMBERS Application October 7,

8 Claims.

This invention relates to the manufacture of electrical devices such ashigh wattage incandescent electric lamps, power tubes, rectiflers orother devices where contact elements are employed for the passage ofheavy currents.

When making a high wattage incandescent electric lamp forexample, it isdesirable, from an operative and practical standpoint to providerelatively large metallic contact pins and considerable difilculty hasheretofore been encountered in sealing the pins in the glass wall of thebulb which forms part of the device.

It has been proposed to provide tubular contacts, termed thimble seals,preferably closed at one end and having the opposite end provided with athin edged funnel shaped opening. These pins are sealed to the wall of abulb by first beading the edges of the open ends with glass and thenheating by means of gas flames to seal the bead to the edges of suitablydisposed openings.

It is an object of the present invention to simplify the method ofattaching contacts to a bulb wall.

Another object of the invention is to provide a method whereby a moreuniform and effective union between a metallic edge and a glass wall isattained. Another object of the invention is to provide a method wherebya plurality of contacts may be simultaneously sealed to a bulb wall.

Other objects and advantages of the invention will be more clearlyunderstood from the following description together with the accompanyingdrawing in which- Fig. 1 shows a portion of a bulb with contacts orthimbles sealed therein in accordance with the present invention;

Fig. 2 shows apparatus for holding a thimble in position to be sealed toa bulb wall and means for heating the glass;

Fig. 3 is a view similar to Fig. 2 but shows the g ass after it has beensoftened and sealed to the edge of a contact member; and

Fig. 4 is a modified form of apparatus for sealing a thimble to a bulband in which the heater is disposed within the end of the thimble.

In devices of the character to which the present invention is mostapplicable a cup-shaped portion III of glass is provided. This cup isprovided with contacts or thimbles II and is then sealed along edge l2to a bulb l3 indicated in dotted lines. The cup may be provided with anexhaust tube It through which the bulb may be evacuated in the usualmanner. Usually the cup is provided with support members to 'which 55electrodes or resistance elements such as tung- 1933, Serial No. 692,587

sten filaments are secured. The cup may, therefore, be constructed toinclude the internal structure or operating elements of the device and aconvenient method is, therefore, had for properly mounting the elementsand for locating them within the bulb. When the cup is fused to the bulbthe device is complete for the sealing-off operation.

. As above mentioned, it has heretofore been proposed to provide thethimbles with glass layers or beads to facilitate their gas-tight unionwith the bulb wall. In the present method, however, this beading isdispensed with.

The wall I5 of the cup is provided with apertures l6 of any desirednumber. The selected embodiment of the invention includes two suchapertures since two contacts are to be used. Each aperture is providedwith an outwardly extending tapered hollow boss or extension l1. Thisboss is so proportioned that it just enters the inner surface adjacentto a tapered edge 20 of a thimble l8. This thimble is flared and isintegral with a tubular cylindrical portion I9 which serves as thecontact proper and enters a socket for the passage of electrical energythrough the device when in operation.

A support 2| having an aperture 22 may be provided to hold the contactelement in position so that the boss I! maybe positioned as shown inFig. 2. In accordance with the present invention a local heat zoneisprovided to soften the glass boss and cause it to wet or stick to theedge 20 of the thimble. In the present construction a heat zone iscreated by means of a resistance element 22' in the form of a helicalcoil which surrounds the tapered edge 20 and the contacting glass boss11. An insulative bafile 23 may be provided to confine the heat for thepurpose intended when current passes through the coil. Any suitablesource of current supply may be used and a switch 24 may be provided toopen and close a circuit including conductors 25 and 26, attached toopposite ends of the coil or resistance element22. When the respectiveparts are in position and the glass boss has been heated to asufficiently plastic state, a member 26 is moved downwardly against theinner edge of the aperture 16 to firmly press the glass against the edge20v and effect a gas-tight seal.

' The member 26 is disposed with its vertical axis in alignment with thevertical axis of the contact members so that as pressure is applied tothe member the contact pin is aligned with the axial line of the tubularboss or extension l1. Thus as heat is applied to soften the glass topermit -ittoflowontotheinnersurfaceofthecontact the member I. inconjimction with the support for the contact pin maintains the properperpendicular relation of the pin with the wall II. In cases whereexceptionally large contact members are employed a heater element 2!(see Fig.

boa ii is rendered plastic and wets with the an edge II and a gas-tightseal is produced. Ob-

viously, if found desirable, the structure shown in Pig. 4 may beprovided with an external heater coil to provide a surrounding zone ofheat to facilitate the sealing operation.

9,5 Although a preferred embodiment of the invention is shown anddescribed herein,-it is to be understood that modifications may be madetherein without departing from the spirit and scope of the invention, asset forth in the appended 30 claims.

I claim:

l. The method of securing a tubular member having an open end to a wallof a glass cup which comprises providing a cup with a tubular pro- 35jection with one endof less diameter than the interior diameter at theopen end of said member, positioning an edge of said tubular memberadjacent to an end of the projection, creating a zone of heat about saidedge to render plastic 4 the end of said projection and in forcingtogether said projection and said member to cause said plastic end ofsaid projection to enter said member and intimately unite the glass withthe interior wall of said member.

2. The method of sealing a tubular member to a glass body whichcomprises providing said body with a tubular projection, positioning theprojection and member end-to-end, locally heating said ends until theglass end has been rendered 50 plastic and in moving the parts togetherwhile said glass is in a plastic state to cause said projection to entersaid member and intimately contact with the inner surface thereof.

3. The method of sealing a tubular metallic 55 member to a glass bodyhaving a tubular projection which comprises, providing a tubular memberwith an open end having an inside-diameter slightly greater than theexternal diameter at the end of said projection, positioning said 50member and projection in axial alignment and with their ends in closeproximity, locally heatme said ends until the glass part becomes plasticand flows into said member in contact with the interior surface of saidtubular member.

4. The method of sealing a tubular metallic member. to a glass bodyhaving a tubular projection which comprises, providing a tubular memberwith an open end having an inside diameter slightly greater than'theexternal diameter at the end of said projection, positioning said memberand projection in axial alignment and with their ends in closeproximity, locally heating said ends until the glass part becomesplastic and flows into the inner surface of said tubular member.

5. The method of sealing a tubular metallic member to a glass bodyhaving a tubular projection which comprises, providing a tubular memberwith an open endhaving an inside diameter slightly greater than theexternal diameter at the end of said projection, positioning said memberand projection in axial alignment and, with their ends in closeproximity, locally heating vsaid ends until the glass part becomesplastic and flows into and in contact with the interior surface of saidtubular member, and in relatively moving said member and body.

6. The method of sealing a tubular metallic member to a glass bodyhaving a tubular projection which comprises, providing a tubularmetallic member with an open end having an inside diameter slightlygreater than the external diameter at the end of said projection,positioning said member and projection in overlapping relation and axialalignment, locally heating said ends until the glass part becomesplastic and flows into contact with the interior surface of said tubularmember. 1

7. The method of sealing a hibular metallic member to a glass bodyhaving a tubular projection which comprises, providing a tubularmetallic member with an open end having an inside diameter slightlygreater than the external diameter at the end of said projection,positioning said member and projection in overlapping relation and axialalignment, locally heating said ends until the glass part becomesplastic and flows into contact with the interior surface of said tubularmember, and in relatively moving said member and projection.

8. The method of sealing a tubular metallic member to a glass bodyhaving a tubular projection which comprises, providing a tubular memberwith an open end having an inside diameter slightly greater than theexternal diameter at the end of said projection, positioning said memberand projection with the open end of said projection extending into theopen end of said member, locally heating said ends until the glass partbecomes plastic and flows into contact with the interior surface of saidtubular member.

HENRY K. RICHARDSON.

